Method of screw-threading sheet-metal tubular objects.



"G. 0.@ T. vv. PALECHECK. IVIVITI-IOD 0F SCREW THREADING SHEET METAL TUBULAR OBJECTS.

v APPLICATION FILED NOV. 6.1917. 19mm? Patented July 2,1918,

@www5/UM illustrates the severa Afurrows.,-

' esA ll lro0 GEURGE D. QP'AlLlECHJECK AND THEODURE W. PALECHECK, 0F MILWAUKEE, WJLSCNSIN.

i METHOD OlE SCREW-THREADING SHEET-METAL TUlBUl-LAR 0133 ECTS.

Specification of Letters Patent.

Patenten Qmit a, loro.,

Vhpplication tiled November 6, i917. Serial No. 200,536.

To all whom t may concern.'

Be it known that we, Gnonon D. PALE- oHEcrr and Tnnononn W, "Pnrucnnon, citizens of the United States, and residents of Milwaukee, in the county of Milwaukee and State, of -Wisconsim have invented certain new and usefulllmprovements in Methods of Screw-Threading Sheet-Metal rllubular (Oh-` jects; and we do lhereby declare that the following is a full, clear, and exact description thereof.

@ur invention refers to 4new and useful improvements 'in methods of forming screw threads on tubular objects formedl from sheet metal and similar material, such as stove pipes, conduit pipes and mailing tubes.

Heretofore it has been practically impossible to form screw threads on sheet metal tubular objects, or those constructed of similar material, 'because of the fact that the threading machines will not operate on such objects when they are seamed. lin other words, the thickness of the joint or'seam in .the pipe or similar object interferes with the formation of the threads, which in suchobjects are in the form of alternate ridges and The object of the present invention is therefore to provide means whereby seamed tubular objects may readily be screwthreaded..

lin carrying cut this object the invention residesin certain novel combination ot steps which will be hereinafter more Vparticularly explained and claimed. l The accompanyin drawing graphically steps, in which: Figure l is a plan view of a fiat sheet of material.,J y y Fig. 2 is a silar view of the same sheet of material after alternate ridges and furrows have been stamped, or pressed, or otherwise' formed therein adjacent its opposite edges.

. Fig. 8 is'an edge view ofthe sheet-shown in ltig. 2, and

Fig.. 4 is a sideelevational view of a pipe constructed in accordance with our invention. v

rlhe principal improvement in the present mlethod of screw threading seamed tubular objects is to construct the corrugations, or the alternate t and furrows, which will V'llhis will cause the op 4ng a Plum-lilly of alternate ridges and fowe at one side and t t @UEM ultimately form the stttw threads, who@ the is in a flat sheet. For instance, the

material numeral 1 designates a Hat sheet of metal or .other material of appropriate and prede-jy termined size for constructing a tubular object of known dimensions, such as a stove pipe of suitable length and diameter.

'llhis sheet of material is next prepared by corrugating the same from end to end adjacent the opposite edges as shown at 2 to form are disposed parallel to each other and at a slight angle to the edges of the sheet, which p are preferably parallel to each other and at right angles to the other edges. The inclination of the corrugations providethe requisite pitch for the screw threads. lf necessary the corrugations may cover the entire sheet, hut when only the ends of the tubular4 object are to be threaded, these corrugations are merely at the opposite sides of the sheet and adjacent the edges thereof.

The next step is to roll sheet in a suitable machine transversely of the ridges and furrows until the opposite ends overlap each other as at 3 in Fig. d. posite ends of the alternate ridges and furrows which 7 5 the corrugated ridges and furrows to aline with each other o complete the formation of the screw threads., v

After this, these overlapped edges may be secured togethery in either hy riveting, as at Il in Fig. 4;, or by crim ing. By this arrangement any sheet meta tubular object may be threaded regardless of the thickness of the sheet.

A further advantage of `this method is that any desired manner,-

the dat sheet may be corrugated in any suitp' able machine and ata vvery considerable rate of speed. Furthermore, these sheets after heing thus prepared may be shipped from vthe factory to the dealer or distributor in a fiat state and formed into a pipe or other tubular object by him. rllhis obviously saves a great amount of space in shipping.

We claim The herein described method of constnucting threaded tubular objects from sheets of material which consists in providing a metallic sheet of certain length and while the same is in a dat state arallel and predetermined out its entire length, said alternate ridges finally securing the overlapped and alined and furrows extending obliquely of said side portions of the sheet together. 13 edge,- rollin said sheet transversely of the In testimony that We claim the foregoing alternate ries and furrows to procure a We have hereunto set our hands at Milwau- 5 tuloularl mem er, alining the ends of the alkee, in the county of Milwaukee and State ternate'ridges and furrows, thereafter overof Wisconsin. lapping the alternate ridges and furrows GEORGE D. PALECHECK. and the adjacent portion of the sheet, and IHEODORE W. PALECHECK. 

